What would cause the engine coolant not to get hot enough?

LES G

MEMBER
2005 CHEVROLET OPTRA
105,000 MILES

This is my first time with a question here. According to temp gauge, car temp sits between 75 and 82.5 Celcius. As a result, car never really warms up inside. Conversely, my other vehicle gets so warm inside that I have to shut off the heater or lower the window. While my initial guess would be the thermosat, on the Optra it is a very expensive guess if I'm wrong. I read something about an engine O2 sensor which may affect engine temp, but I know nothing about that. What do you folks believe would cause this issue? Thanks.

1 Reply

HMAC300

MECHANIC
48,601 POSTS

Make sure both hoses going to heater are hot. Then if they are check the actuators on your heater unit under the dash, they can be either vacuum or electric. One of them may not be working. If thehoses aren't hot then replace the thermostat.